A backplane for an electro-optic display including an electrode and a substrate. The substrate may be porous to liquids, e.g., water, and may formed, from cellulose or a similar hydrophilic polymer. The electrode is desirably also porous to the same liquid as the substrate, so that the electrodes do not form liquid-impervious areas on the substrate. For example, when the liquid is water (or an aqueous solution) the electrodes may be formed of a hydrophilic carbon black, which may be coated or screen-printed on to the substrate.